Spoken communication between individuals is a fundamental aspect of human nature. Delays, pauses, interruptions, overtalking, etc. may convey, intentionally or unintentionally, a meaning beyond the words themselves. One significant problem with calls, especially cell phone, voice over IP, or voice/video conference calls, is that there can be serious transmission and codec encoding/decoding delays, which substantially affect interactions. There are also cultural aspects to conversations that should be considered. For example, a longer pause in Japanese might be indicative of respect. The manner in which people interact and factors that impact conversation are large concerns for contact centers.
Anyone that has made a call between two cell phones in the same room has likely experienced this large delay firsthand—speaking into one phone, the voice is reproduced on the second handset over a second later.
On the other hand, the delay on a landline PSTN link or VoIP equivalent can be quite low. A G.711 codec has negligible delay other than the frame and packetization delay of 10 or 20 ms. Transmission may add 60-80 ms, and so the end to end delay will typically be under 150 ms.
A customer's perception of the agent and/or the company may be adversely affected based on the conversation delay being inappropriate. On the other hand, a customer may be well-aware of the delay and may think a contact center agent is quite responsive and helpful; however, a post hoc analysis of a highly-delayed call may result in the contact center agent being given a poor grade even though the agent was doing everything within their power to provide the appropriate amount of customer service.